1. A sinusoidal oscillator, characterized in that it comprises on a single integrated circuit chip a first selective band-pass filter (F1) having a transmission maximum at a central frequency Fo and comprising an input (E1) and an output (S1), a feedback loop (A1) which connects the input and the output to form an oscillator at the frequency Fo, a second selective band-pass filter (F2) identical to the first and comprising an input (E2) which is connected directly or through the intermediary of an attenuator (ATT) to the output of the first filter, and an output (S2) which constitutes the output of the sinusoidal oscillator.

Sinusoidal oscillator with very low distortion

Vorrichtung fuer die magnetische therapie

The oscillator controlled by an electromechanical resonator with stabilization of output voltage of the present invention comprises a control loop with an optocoupler for stabilization of the output voltage amplitude. The oscillator further comprises a first operational amplifier (OA1); with an electromechanical resonator, (X1) connected in a loop of a positive feedback and with an optocoupler (3) photoresistor (PR) connected parallel to a resistor (R5) in the loop of a negative feedback. The output voltage stabilizer comprises a second operational amplifier (OA2) with a circuitry as a rectifier and amplifier and connected to the optocoupler (3) luminescent diode (LED).

Electromechanical resonator-controlled oscillator

L'invention concerne un generateur sinusoidal a tres faible distorsion. Pour realiser un generateur sinusoidal a tres faible distorsion on utilise deux filtres (12,14) selectifs de caracteristiques identiques realises sur une meme puce de circuit integre. L'un des filtres (12) est boucle en oscillateur a frequence Fo et l'autre (14) sert de filtre dont le pic est justement a meme frequence Fo. L'application est particu­lierement interessante avec des filtres a capacites commutees pour lesquels on peut facilement regler la frequence centrale Fo.

Oscillateur sinusoidal à très faible distorsion

To generate a harmonic-free sine-wave oscillation whose frequency can be modified continuously within specific limits depending on a control current supplied from an external voltage source, an active low-pass filter is connected downstream of the oscillator which, in the same way as the frequency of the oscillator, is varied in terms of its limit frequency by the control current, and this control current flows through the LEDs contained in optocouplers which in turn illuminate photoresistors whose resistance value which is dependent on the radiation intensity is frequency-defining in the oscillator and limit-frequency-defining in the low-pass filter. If, for example, the frequency of the oscillator increases due to an increasing control current, the same control current will likewise increase the limit frequency in the active low-pass filter to such an extent that the fundamental wave can pass unchanged, whereas all the harmonics are blocked.

Robok Alfred

Papers

Voltage-controlled sine-wave oscillator